Okay I had not heard there was a suspicious other vehicle. I dont' think SMcD did it. He was sending her text and emails about the upcoming camping trip? His car was seen around back, so you are saying that is nothing out of the ordinary as others have implied otherwise
(You wrote:The fact that even the downstairs neighbor heard anything that stood out makes me wonder if she were, in fact, outside and downstairs), so you mean that maybe the lady neighbor wasn't home at the time or was inside if Lauren was lured into the other (suspicious) car that has been mentioned. Well if so, then that would imply the killer wasn't from the complex and then brought the torso back. Which doesn't seems like a lot of trouble to me but it does confuse the LE.
But If McD was hasty in his disgarding on wednesday late night or early morning Thurs would seem to make better sense, but there's a lot of other things brought up that doesnt' point to him at all.
He has one car, correct? So it would make sense that nothing took place onsite at Barrister because there was nothing immediately damming that got anyone arrested for immediately and there was nothing suspicious heard or seen, but apparently that car that LE inquired about to his mom.
So it would suggest as you say, she was lured but someone brought the torso back, and now they are looking at McD who might be innocent instead of looking hard for some psycho seriel killer or mass murderer. Myabe it was some initiation, she being so nice, someone may have pretended to be lost but go out there at night alone not knowing them? Oh mercy. Even if it is quiet there, dont' approach someone's car you dont' know, EVER....JMT